Browse Topic: Oxygen

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Biofuel Effect on Regeneration Capability and Soot Reactivity in SCRoF Systems2026-01-07507/1/2026
Biodiesel blends (B7, B20, B100) were evaluated in a Stage V-compliant SCR on Filter (SCRoF) system for heavy-duty applications to quantify soot reactivity and filter regeneration capability. Compared to conventional diesel (B7), B20 showed slightly faster regeneration performance under real-driving conditions, while B100 resulted in reduced particulate formation and higher soot reactivity, with more intense exothermic events requiring careful management. These differences are attributed to the distinct physical-chemical properties of the fuels (oxygen content, lower heating value) and their interaction with Diesel Oxidation Catalyst (DOC)/SCRoF. All tests were conducted on an engine dynamometer with a Cursor 9 FPT (Fiat Powertrain). Findings are discussed in the context of EU Stage V limits and practical control strategies for heavy-duty applications.
Costa, Simone
Study on the Performance of High-Pressure Oxygen Cylinder Oxygen Supplemental System in Civil Aircraft Lavatories Based on Airworthiness Oxygen Requirements2025-99-030712/17/2025
This paper focuses on the performance of the high-pressure oxygen cylinder oxygen supplemental system in the lavatory of civil aircraft. Due to the potential safety hazards of chemical oxygen generators in the lavatory, high-pressure gaseous oxygen cylinders are used instead. Through theoretical and study, the influence of the orifice on the oxygen flow rate is thoroughly investigated. Based on relevant principles, the calculation method of the gas flow characteristics in the orifice is determined. Considering the high initial pressure of the oxygen cylinder, the supersonic flow condition within approximately 20 minutes is mainly considered. The Simulink is used to simulate the system flow rate under different temperatures during cabin depressurization. Experimental verification shows that the oxygen flow rate under different temperatures meets the minimum oxygen demand, and the simulation results are highly consistent with the experimental results, indicating that the simulation accuracy meets the airworthiness standards and provides a strong basis for the design and optimization of the system.
Wan, Shuting, Lei, Mingjun, Yu, Xiaoying
Experimental and Kinetic Study of Methane Blending on The Laminar Combustion and Emission Characteristics of Ammonia Under Various Oxygen Contents at High Temperature and Pressure2025-32-006011/3/2025
As a carbon-free fuel, ammonia is one of the alternatives to traditional fossil fuels, but its combustion characteristics are poor, and it is usually optimized by blending methane and increasing oxygen content. However, there are few relevant studies under different conditions. In this study, the laminar burning velocities (LBV) and flame instability of NH3/CH4/O2/N2 mixture at high initial temperature (T), high initial pressure (p), various oxygen contents (Ω) and methane energy ratios (α) are analyzed using a constant volume combustion chamber (CVCC). Through numerical simulation, how various oxygen contents and methane energy ratios affect the combustion characteristics of NH3/CH4/O2/N2 mixture and NO emission is analyzed. The results show that LBV is positively correlated with T, α and Ω, and negatively correlated with p. Markstein length (Lb) does not change significantly with T, but increases with α and decreases with p and Ω. Both oxygen enrichment and methane blending significantly increase the hydrodynamic instability of the flame and decrease the buoyancy instability of the flame. Oxygen enrichment and methane blending have little effect on the thermal diffusion instability of the flame. Oxygen enrichment and methane blending are effective in increasing the generation of NHi, O, H, OH, and other radicals and the chemical reaction rate. The main factor of oxygen enrichment and methane blending to increase LBV is the thermal effect, but it also leads to the increase of NO, which is mainly thermal NO. The reaction path and sensitivity analysis of NO show that HNO + H <=> NO + H2, N + NO <=> N2 + O play an important role in the production and consumption of NO, respectively. With the change of Ω and α, the concentration of NO increases and the time of NO production decreases.
YU, Yuantao, Dai, Zhizhuo, Hou, Chunlei, Ye, Mingyuan, Zhang, Xiaolei, Cui, Zechuan, Yin, Shuo, Nishida, Keiya
3D CFD Analysis of Flow and Thermal Dynamics of PEM Water Electrolyzer2025-28-035010/30/2025
The proton exchange membrane (PEM) water electrolyzer is an emerging technology to produce green hydrogen due to its compactness and producing high purity hydrogen. This study presents a numerical investigation on multiphase flow dynamics and heat transfer within the anode flow field of a PEM water electrolyzer. Two different channel configurations, i.e., rectangular, semi-circular are considered having same cross-sectional area while keeping the porous transport layer (PTL) thickness constant (which is within the commercially available ranges). Simulations are conducted for various oxygen generation rates and heat fluxes (corresponding to different current densities) and different inlet water flow rates. The effects of channel configurations on pressure drop, flow uniformity, and temperature distribution are illustrated pictorially and graphically. The impact of water flow rates and oxygen generation rates on phase distribution, pressure drop, and temperature profiles, particularly focusing on hot spot regions and oxygen starvation regions are investigated thoroughly. Detailed oxygen concentration distributions and temperature contours at various locations are depicted for different geometrical and operating condition that are crucial for effective functioning of the membrane. This study brings out the importance of channel configurations, operating current densities on PEM water electrolyzer performance. The insights gained are expected to guide the design of new anode plates, aiming to mitigate issues such as hot spots and oxygen starvation, ultimately leading to improved efficiency and reliability of PEM water electrolyzer in sustainable hydrogen production.
Dash, Manoj Kumar, Bansode PhD, Annasaheb
Selecting the Best Plastic for Spacecraft Applications25AERP10_0310/1/2025
Plastic materials are used for a wide variety of spacecraft applications including seals, bearings, fasteners, electrical insulators, thermal isolators, and radomes. Selecting plastics for use in space is complex due to wide operating temperature ranges, vacuum conditions, and exposure to radiation and atomic oxygen. Additionally, some spacecraft applications require sealing flammable propellants such as hydrogen and oxygen. This article will present some design considerations when selecting plastics for use in spacecraft. It will provide rich data on the performance characteristics of plastics as well as examples of successful spacecraft applications.
Passive Nutrient Delivery System (PONDS)TBMG-5392610/1/2025
Reliable seed germination and plant production requires an environment that is neither too dry nor too wet. PONDS was developed to improve water and nutrient delivery for plants grown on the International Space Station (ISS). The technology uses an innovative wicking material to passively link a water/nutrient reservoir to a growth cylinder where seeds are germinated and plants are produced. PONDS addresses limitations with existing ISS plant-production technology by providing consistent delivery of water/nutrients, improving oxygen transfer to plants, and allowing users to determine how much water is being applied.
Enabling Near-Zero Emissions and Superior Efficiency in Large-Bore, Medium-Speed Engines with a Hydrogen-Argon Power Cycle2025-24-00019/7/2025
Combustion engines operating on a hydrogen-argon power cycle (H-APC) offer potential for superior thermal efficiency with true zero exhaust emissions. The high specific heat ratio of argon allows extrapolation of the theoretical efficiency of the Otto cycle to almost 90%. However, this potential is significantly constrained by challenges in combustion control, excessive thermal loading, and system integration, particularly regarding argon recovery. This study investigates these trade-offs, within the context of real-world engine-based peaking power plants. An experimentally validated 1D-simulation model of a prototype Wärtsilä 20 DF engine serves as reference for analysis of a retrofit incorporating a closed-loop argon cycle, with dedicated H₂ and O2 injectors, a water condenser and water separator. Engine performance is evaluated at reference operating point of 75% load, considering pre-ignition, peak pressure and exhaust temperature constraints, condenser limitations, and impurity accumulation. Argon emerges as the best monoatomic gas for H-APC. Helium, the second-best candidate, offers superior thermal conductivity and specific heat, but its low density and molecular weight reduce power output. A 90% argon and 10% oxygen mixture offers the optimal trade-off between power output, efficiency, and durability. A compression ratio of 11.90:1 ensures stable combustion within design constraints, while stoichiometric operation and condenser inlet pressure of 3.23 bar enhances performance, achieving the best indicated gross efficiency of 59.10%. This is over 10 percentage points better than the reference engine at 75% load. Nevertheless, practical implementation is limited by pumping losses in a packaging-optimized argon-path layout, reducing extractable efficiency to 56.70%. Furthermore, just 2% impurities in fuel/oxidizer stream causes progressive efficiency decline, falling below the reference threshold after approximately 10 minutes of operation. This highlights the necessity of a membrane-based separator and system volume optimization. The findings establish a validated computational framework for optimizing closed-loop hydrogen combustion and provide valuable insights for progressing demonstrator development.
Ahammed, Sajid, Ahmad, Zeeshan, Mahmoudzadeh Andwari, Amin, Kakoee, Alireza, Hyvonen, Jari, Mikulski, Maciej
Laser Welding for Polymer Tubing: A New Solution for Adhesive- and Additive-Free JoiningTBMG-537789/1/2025
Medical tubing is an essential component of countless healthcare applications, from intravenous (IV) and oxygen lines to catheters and diagnostic equipment. These tubes, often made of clear flexible polymers, must be produced to exacting standards: free of contaminants, strong under pressure, and biocompatible. However, the joining process to connect these tubes can introduce significant manufacturing challenges.
Fuel Versus Oxygen: Evaluations and ConsiderationsAIR5648B (Current)7/9/2025
Current regulations (e.g., Title 14 of the United States Code of Federal Regulations, or 14 CFR) define design requirements for oxygen system provisions for protection of crewmembers and passengers following emergency events such as in-flight decompression. This aerospace information report (AIR) addresses the operational oxygen system requirements for a decompression incident that may occur at any point during a long-range flight, with an emphasis for a decompression at the equal time point (ETP). This AIR identifies fuel and oxygen management contingencies and presents possible solutions for the efficient, safe, and optimum fuel/oxygen flight continuation. Oxygen management is a critical concern for all aircraft, ranging from single-engine types operating above 10000 feet to complex, high-performance aircraft equipped with supplemental oxygen systems. Proper planning ensures compliance with regulations and supports pilot and passenger safety at higher altitudes. This document provides a method which can help guide users in developing an oxygen solution for their aircraft. This document is not intended to change, modify, or alter any existing design or installation procedure and has been mostly developed for flight operations.
A-10 Aircraft Oxygen Equipment Committee
Investigating Lubricants Base Oils Reactivity in Ammonia Engines via Accelerated Aging2025-01-02406/16/2025
As a carbon-free molecule, ammonia is more and more considered as a relevant fuel for long distance and off-road applications. However, this gas has different combustion characteristics compared to conventional fuels, challenging the suitability of lubricants to such engines. In this work, the evolution of lubricants under conditions mimicking ammonia combustion was assessed. Mineral and polyester lubricant base oils were exposed to oxygen, nitrogen oxides, and ammonia in a pressurized reactor under stirring. Oil aliquots were sampled at regular intervals, and characterized using Fourier Transform Infrared Spectroscopy (FTIR), viscosity and total oxygen and nitrogen contents measurements. Exposure to air containing nitrogen oxides resulted in quicker accumulation of oxidation products compared to neat air, for both the mineral and complex polyester base oil. Besides, exposure to gaseous ammonia in air resulted in a slower oxidation rate for both oils, compared to neat air. A global measurement of the total nitrogen content after 2 h showed a significant increase for both oils. Under similar conditions, the total nitrogen content of the polyester base oil was higher than the mineral oil, indicating a higher affinity of the ammonia with this matrix. Chromatograms obtained with a Gas Chromatography (GC) column associated to a Nitrogen Chemiluminescence Detector (NCD) showed that nitrogen speciation evolved from nitrogen contained in very light molecules, likely dissolved ammonia, to molecular nitrogen distributed across the entire range of hydrocarbon chain lengths. This demonstrates that ammonia reacted with the base oils and their degradation products. Two-dimensional gas chromatography and mass spectrometry will be performed in the upcoming months to identify these new kinds of degradation products. This study paves the way towards a better understanding of oil reactivity when exposed to ammonia combustion byproducts, including outcomes on engine operation and emissions of pollutants.
Doncoeur, Carole, Giarracca, Lucia, Cologon, Perrine, Rousselle, Christine
Methodology for Selection of Gasoline Catalytic Convertor & Oxygen Sensor Position, Study on Oxygen Storage Capacity for 1.2L Turbocharger MPFI Engine2025-01-50225/16/2025
The results published in this paper emphasize on the study of three-way catalytic convertor for a 1.2 L turbocharged multi-point fuel injection gasoline engine. This paper takes us through the findings on methodology used for finalizing the brick configuration for catalytic convertor along with downstream oxygen sensor placement for emission control and methods applied for catalytic convertor selection with actual testing. The advantages of dual brick configuration over single brick with downstream sensor placed in between the bricks to enable faster dew point of sensor is explained using water splash test and design confirmation of better exhaust gas flow vortices concentration at the sensor tip for better sensing. Selection of catalytic convertor loading by testing its emission conversion capability and light-off behavior. NOx conversion capability across stoichiometric ratio (14.7:1 for petrol) on selected most operational zone was tested (±5% lambda) for the design-finalized samples acquired for testing. Also ability of faster light-off temperature (250–300°C) where conversion efficiency should be >95% is evaluated. Like wise it was also found that emission conversion efficiency is directly proportional to oxygen storage capacity of catalytic convertor with same configuration. On the other hand, an experiment on reverse aging for catalytic convertor was performed to monitor its improvement in oxygen storage capacity.
Arun Selvan, S. A., Paul, Arun Augustine, Selvaraj, Manimaran
Accelerated Reactive Force Field Molecular Dynamics Simulation on the Diffusion Process in Ni/YSZ Anode of SOFCs with Collective Variable-Driven Hyperdynamics2025-01-85544/1/2025
Due to advantages such as high efficiency, low emissions, and fuel flexibility, solid oxide fuel cells (SOFCs) have garnered significant attention as promising power sources for automotive applications. Nickel/yttria-stabilized zirconia (Ni/YSZ) is one of the most widely used anode materials in SOFCs, as it can catalyze both chemical and electrochemical reactions of carbon-containing fuels. However, the direct use of carbon-containing fuels can lead to carbon deposition on the Ni/YSZ anode, negatively impacting the performance and reliability of automotive SOFC systems. The diffusion of carbon atoms within nickel plays a crucial role in the carbon deposition process and requires further investigation. The oxygen atoms that spillover from YSZ also participate in main reactions such as carbon deposition and electrochemical reactions in Ni. Molecular dynamics (MD) is one of the main methods for studying atomic diffusion in crystalline structures. In this study, reactive force field molecular dynamics (ReaxFF-MD) models of Ni and Ni/YSZ crystal structures are established. The operating temperature of automotive SOFCs is typically 500-700°C, which results in a low frequency of diffusion events in the ReaxFF-MD model, leading to high computational costs. Therefore, an acceleration technique known as collective variable-driven hyperdynamics (CVHD) is employed to extend the time scale of the simulations. The diffusion coefficient of carbon atoms in nickel at low temperatures is calculated. Additionally, the spillover process of oxygen atoms in YSZ is considered, and the diffusion coefficients of oxygen atoms in both Ni and YSZ are calculated. The Arrhenius equation parameters for carbon and oxygen diffusion in nickel are determined, laying the foundation for further studies on the mechanisms of carbon deposition and oxidation on Ni/YSZ anode materials.
Du, Haoyu, Zhang, Kaiqi, Xiao, Ma, Zhang, Xiaoqing, Shuai, Shijin
Fundamental Science on Oxygen Storage Capacity of Cerium Complex Oxides for Advanced On-Board Diagnostics (2) Quantitative Observation of Oxygen Released from Cerium Complex Oxides2025-01-84764/1/2025
In order to comply with the tightening of global regulations on automobile exhaust gas, further improvements to exhaust gas control catalysts and upgrades to on-board diagnostics (OBD) systems must be made. Currently, oxygen storage capacity (OSC) is monitored by front and rear sensors before and after the catalyst, and deterioration is judged by a decrease in OSC, but it is possible that catalyst deterioration may cause the rear sensor to detect gas that has not been sufficiently purified. It is important to observe the activity changes when the catalyst deteriorates in more detail and to gain a deeper understanding of the catalyst mechanism in order to create guidelines for future catalyst development. In this study, we used a μ-TG (micro thermogravimetric balance) to analyze in detail how differences in design parameters such as the type of precious metal, detection temperature, and mileage (degree of deterioration) affect the OSC rate in addition to the OSC of the ceria-based composite oxide of the entire catalyst. It was found that CZY has better durability in terms of both OSC rate and amount than CZ. Furthermore, by comparing the results of experiments using time-resolved dispersive X-ray absorption fine structure (DXAFS) using synchrotron radiation, the reduction behavior of ceria was analyzed in more detail.
Hamada, Shota, Uegaki, Shinya, Tanabe, Hidetaka, Nakayama, Tomohito, Jinjo, Itsuki, Kurono, Seita, Oishi, Shunsuke, Narita, Keiichi, Onishi, Tetsuro, Yasuda, Kazuya, Matsumura, Daiju, Tanaka, Hirohisa
Fundamental Science on Oxygen Storage Capacity of Cerium Complex Oxides for Advanced On-Board Diagnostics (1) Kinetic Observation of Cerium Valence Change Using Synchrotron Radiation2025-01-84744/1/2025
On-board diagnosis (OBD) of gasoline vehicle emissions is detected by measuring the fluctuations of the rear oxygen sensor due to the time-dependent deterioration of the oxygen storage capacity (OSC) contained in the automotive catalyst materials. To detect OBD in various driving modes of automobiles with an order of magnitude higher accuracy than before, it is essential to understand the OSC mechanism based on fundamental science. In this study, time-resolved dispersive X-ray absorption fine structure (DXAFS) using synchrotron radiation was used to carry out a detailed analysis not only of the OSC of ceria-based complex oxides, which had previously been roughly understood, but also of how differences in design parameters such as the type of precious metals, reducing gases (CO and H2), detection temperatures, and mileages (degree of deteriorations) affect the OSC rate in a fluctuating redox atmosphere. A fundamental characteristic was clearly demonstrated in ceria-based complex oxides: the oxygen release rate accompanying the generation of oxygen vacancies is overwhelmingly slower than the oxygen storage rate that restores the crystal structure. Another interesting result was revealed: when precious metals are supported, a competitive reaction occurs between the precious metal and the ceria-based complex oxide in the release/storage of oxygen, and the change in cerium valence from tetravalent to trivalent actually slows down. Furthermore, it was proven that CZY is more durable than CZ in terms of both OSC rate and amount. In this way, the basic scientific properties of ceria-based complex oxides, which are necessary for designing OBD logic, have been clarified.
Tanaka, Hirohisa, Matsumura, Daiju, Uegaki, Shinya, Hamada, Shota, Aotani, Takuro, Kamezawa, Saeka, Nakamoto, Masami, Asai, Shingo, Mizuno, Tomohisa, Takamura, Riku, Goto, Takashi
Cryogenic Flux CapacitorTBMG-524772/1/2025
NASA's Cryogenic Flux Capacitor (CFC) capitalizes on the energy storage capacity of liquefied gases. By exploiting a unique attribute of nano-porous materials, aerogel in this case, fluid commodities such as oxygen, hydrogen, methane, etc. can be stored in a molecular surface-adsorbed state. This cryogenic fluid can be stored at low to moderate pressure densities, on par with liquid, and then quickly converted to a gas, when the need arises. This solution reduces both safety-related logistics issues and the limitations of complex storage systems.
Cryogenic Oxygen Storage Modules (COSM)TBMG-524782/1/2025
NASA Kennedy Space Center engineers developed a Cryogenic Oxygen Storage Module (COSM) to store oxygen in solid-state form and deliver it as a gas to an end-use environmental control and/or life support system. Additionally, the COSM can scrub out nuisance or containment gases such as carbon dioxide and/or water vapor in conjunction with supplying oxygen, forming a synergistic system when used in a closed-loop application.
Mesoscopic Heat and Mass Transfer Process in Catalyst Layer of Proton Exchange Membrane Fuel Cells under Cold Environment2025-01-70881/31/2025
To explore the heat and mass transfer processes within the low-temperature catalyst layer, a coupled heat and mass transfer lattice Boltzmann model and electrochemical model were established, creating a pore-scale model for heat and mass transfer in the catalyst layer. The influence of the catalyst layer parameters was investigated. The results indicate that as time progresses, heat gradually accumulates at the top of the catalyst layer (CL) and is transmitted towards the bottom. Once oxygen enters the CL, it quickly fills the pores within the CL, resulting in a rapid decrease in oxygen concentration within the ionomer. As the platinum volume fraction increases, there is a significant rise in temperature across the entire calculation domain. With the increasing platinum volume fraction, the current density also increases rapidly due to the larger reaction area. When the carbon volume fraction is 0.15, more oxygen enters the ionomer to participate in reactions, and the large porosity enhances thermal convection, leading to the highest temperature at this point. As the ionomer content increases, the area of the high-temperature red zone within the CL also expands. However, with a carbon volume fraction of 0.25, the diffusion of oxygen in the pores is reduced, leading to most of the oxygen entering the ionomer, resulting in the highest current density among the three cases. Nonetheless, since thermal convection is stronger when the I/C weight ratios is relatively small, the overall temperature remains high. As the I/C weight ratios increases, oxygen diffusion weakens, and the overall current density shows an upward trend.
Xu, Sheng, Chen, Xin, Sheng, Tao
Cracking Activity and Characterization of Magnesium Titanium Dioxide - Silicon Dioxide Catalysts2024-01-524112/10/2024
Purified nickel and a large number of MgTi2 / NiO2 catalysts with various MgTi2 loadings were produced using the traditional incipient wetness method. X-ray crystallography and Fourier-transform infrared spectroscopy were used to examine the catalysts. To understand the material's microstructure better, the researchers investigated oxygen adsorption at 90K. The amine titration method was used to investigate the acidic characteristics of these catalysts. In a study on cumene cracking, these catalysts were employed. The catalyst was found to be amorphous up to a loading of 12 weight percent MgTi2, but at higher loadings, crystalline MgTi2 phase formed on an amorphous silica substrate. When NiO2 is doped with more MgTi2, there are significant differences in the structure, surface acidity, and catalytic activity of the catalysts. Catalysts with a higher MgTi2 loading are noticeably more acidic than those with a lower MgTi2 loading. A correlation between the amount of cracking activity and the number of acid sites on the catalyst surface has been shown in numerous studies. Cumene cannot be cracked over the investigated catalysts unless the catalyst contains extremely acidic sites. Unmistakably Bronsted acid sites, with the breaking action attributed to a mechanism involving chromium ions. The results were validated by comparing them with relevant studies in the existing literature. These comparisons demonstrate consistency with similar research, confirming the effectiveness of the MgTi2/NiO2 catalysts.
Ashok Kumar, B., Dhiyaneswaran, J., Selvaraj, Malathi, Pradeepkumar, M., Shajeeth, S.
Smart Full-Body Fitness TrackingTBMG-5172010/1/2024
I’m guessing that when you think about applications for AI, physical fitness is not the first thing that comes to mind. But it is actually one of the more common applications. The most popular fitness sensors use AI to keep track of how many steps you’ve taken, track your progress, and integrate that with health information like heartrate or even blood oxygen level. But AI can do much more than that.
Oxygen Flow IndicationAS916C (Current)9/13/2024
This SAE Aerospace Standard (AS) defines the overall requirements applicable to oxygen flow indication as required by Airworthiness Requirements of CS/FAR 25.1449 to show that oxygen is being delivered to the dispensing equipment. Requirements of this document shall be applicable to any type of oxygen system technology and encompass “traditional” pneumatic devices, as well electric/electronic indication.
A-10 Aircraft Oxygen Equipment Committee
“Performance Emission Parameters Behavior of a DI Diesel Engine Using Al 2 O 3 and TiO 2 Nano Additive Biodiesel Blends”2023-28-012711/10/2023
This study mainly focuses on the blending of Alumina and Titanium oxide nanoparticles (NP’s) in Spirulina biodiesel blends (SB20) to estimate the influence of engine (combustion, performance and emission) parameters of a diesel engine. The characterization of Al2O3 and TiO2 NP’s like SEM were reported. By using various fuel samples such as Diesel, SB20, SB20+40 ppm AO, SB20+80 ppm AO, SB20+40 ppm TO and SB20+80 ppm TO, the engine tests on the diesel engine were conducted at various load conditions. The BTE for SB20+80 ppm AO were enhanced by 12.35% and 8.4 % compared to the SB20 fuel and SB20+40 ppm AO fuel samples. The combustion parameters were improved for the NP’s as additives (Al2O3 and TiO2) fuels than the SB20 fuel sample because NP’s contain oxygen content. The parameters of engine exhaust emissions such as HC, CO and smoke are drastically diminished for the SB20+40 ppm AO, SB20+80 ppm AO, SB20+40 ppm TO and SB20+80 ppm TO fuels compared to the SB20 fuel. A marginal improvement was observed for the NP’s blended fuel samples in case of NOx emissions than the B20 fuel.
Anchupogu, Praveen, Krupakaran, R L, Ganipineni, Jamuna Rani, Petla, Ratna Kamala
A Kinetic Modeling and Engine Simulation Study on Ozone-Enhanced Ammonia Oxidation2023-01-163910/31/2023
Ammonia has attracted the attention of a growing number of researchers in recent years. However, some properties of ammonia (e.g., low laminar burning velocity, high ignition energy, etc.) inhibit its direct application in engines. Several routes have been proposed to overcome these problems, such as oxygen enrichment, partial fuel cracking strategy and co-combustion with more reactive fuels. Improving the reactivity of ammonia from the oxidizer side is also practical. Ozone is a highly reactive oxidizer which can be easily and rapidly generated through electrical plasma and is an effective promoter applicable for a variety of fuels. The dissociation reaction of ozone increases the concentration of reactive radicals and promotes chain-propagating reactions. Thus, obtaining accurate rate constants of reactions related to ozone is necessary, especially at elevated to high pressure range which is closer to engine-relevant conditions. In present work, rate constants of ozone dissociation reaction were recalculated and extended to cover engine-relevant pressure conditions based on multiconfigurational calculation results in literature. A kinetic model was developed based on calculated results in present work and data taken from literature. This model was further used for numerical simulations of ozone-enhanced ammonia oxidation at pressures of 1-5 MPa and temperatures ranging from 700-1000 K. Kinetic analysis based on Chemkin simulation was performed to investigate and evaluate the effect of ozone addition. Engine simulation was also performed to investigate the feasibility of ozone-enhanced ammonia oxidation in engine applications. Present work investigates a different route of enhanced combustion of ammonia and will contribute to the future application of ammonia in engines.
Zhang, Zhenyingnan, Li, Ang, Li, Zhuohang, Zhu, Lei, Huang, Zhen
Transcritical Mixing of Fuels at Reactive Conditions2023-32-01179/29/2023
Although progress has recently been made to characterise the transition of microscopic liquid fuel droplets from classical evaporation to a diffusive mixing regime, still little is known about the transition from one to the other under reactive conditions. The lack of experimental data for microscopic droplets at realistic operating conditions impedes the development of phenomenological and numerical models for droplet mixing, ignition, combustion and soot formation. In order to address this issue we performed systematic measurements using high- speed long-distance microscopy, for n-dodecane into gas at elevated temperatures (from 750 to 1,600 K) and pressures up to 13 MPa. We describe these high- speed visualizations at the microscopic level, including the time evolution of the liquid droplets, reaction wave, and soot distribution. Our measurements show that these parameters are influenced by the operating conditions (gas pressure, gas temperature, oxygen content) as well as the physical properties of the fuel.
Crua, Cyril, Manin, Julien, Skeen, Scott, Pickett, Lyle M
Numerical Study on the Effect of Injector Nozzle Hole Number on Diesel Engine Performance under Plateau Conditions2023-24-00338/28/2023
Diesel engines operated at high altitudes would experience performance degradation due to the fuel-air amount mismatch, resulting in combustion deterioration. Technologies that supplement oxygen concentration, such as intake oxygen enrichment, turbocharging and the addition of oxygenated fuel additives, can help restore performance at high altitudes, but each has its own limitations Operating diesel engines at high altitudes still generates extremely lean fuel-air mixtures, making the improved utilization of excess air the most economically efficient approach to optimize engine performance under such conditions. The objective of this paper is to investigate the effects of injector nozzle-hole numbers on diesel engines operated at high altitudes, a topic that has been limitedly discussed in existing literature, with the aim of enhancing understanding regarding the potential of this cost-effective approach and aiding in the design of a cooperative approach between oxygen concentration supplementation techniques and better oxygen utilization techniques, ultimately optimizing engine performance at high altitudes. The results suggest that increasing the number of nozzle-holes enhances fuel-air mixing, leading to improved combustion quality and enhancing the engine’s adaptability to altitude. However, at extremely high altitudes, such as altitudes exceeding 3000 meters, configurations with a larger number of nozzle-holes still exhibit high concentrations of incomplete combustion products, such as soot emissions, in the exhaust. This reduced combustion efficiency is mainly attributed to the longer spray penetration length at high altitudes, which causes intensified spray impingement on the cavity wall, subsequently resulting in inefficient combustion of the fuel flowing into the squish zone during spray impingement. This inefficiency may be mitigated by optimizing the shape of the combustion chamber. It is worth noting that increasing the number of nozzle-holes can also lead to a higher pressure rise rate. Considering that high altitude operations already result in a higher pressure rise rate, further increasing the nozzle-hole number may exceed the allowable threshold and increase the likelihood of engine component failure. Consequently, the strength of engine components becomes a limiting factor when attempting to increase the number of nozzle-holes for improved engine altitude adaptation.
Zhao, Junliang, Yang, Ruomiao, Yan, Yuchao, Ou, Juan, Liu, Zhentao, Liu, Jinlong
Crew Member Oxygen Regulators, DemandAS8027 (Current)8/23/2023
This SAE Aerospace Standard (AS) is intended to apply to those oxygen regulators which supply gaseous oxygen at breathing pressures to meet physiological requirements of aircraft flight crew members. It defines the minimum performance requirements and testing for aircraft demand type breathing oxygen regulators.
A-10 Aircraft Oxygen Equipment Committee
Oxygen System Maintenance GuideAIR1392A (Current)8/23/2023
This document is intended to give general instructions and directions for personnel performing maintenance and modification work on Oxygen Systems.
A-10 Aircraft Oxygen Equipment Committee
Liquid Oxygen SystemsAIR825/5A (Current)8/23/2023
This Aerospace Information Report provides general information to aircraft designers and engineers, regarding LOX, its properties, its storage and its conversion to gas. Much useful information is included herein for aircraft designers regarding important design considerations for a safe and effective installation to an aircraft. The associated ground support equipment needed to support operations of LOX equipped aircraft is also discussed. It is important to realize that LOX equipped aircraft cannot be supported unless this support infrastructure is also available. A significant part of this document will address the specific advantages, disadvantages and precautions relating to LOX systems. These are important issues that must be considered in deciding which oxygen system to install to the aircraft. Also, many commercial and military aircraft use aeromedical LOX equipment that is mostly portable equipment. Aeromedical LOX equipment is not addressed herein as it is beyond the scope of this document.
A-10 Aircraft Oxygen Equipment Committee
Aviator's Breathing Oxygen Purity StandardAS8010D (Current)8/23/2023
This document defines the minimum degree of purity and maximum levels of certain deleterious impurities allowable for aviator's breathing oxygen at the point of manufacture or generation. It covers gaseous, liquid, and chemically generated oxygen, and oxygen supplied by in situ concentration and in situ electrolysis. Different limits are established for oxygen from different sources, in recognition of differences in the ways the oxygen is stored, dispensed, and utilized, taking into account the safety of the user. These limits are not intended to specifically reflect upon the relative capabilities or merits of various technologies. Procurement documents may specify more stringent limits, where required for specific applications. Medical oxygen is not covered by this standard. In the United States, medical oxygen is a prescription drug and complies with the United States Pharmacopoeia (USP). In Europe, medical oxygen specification compiles with the European Pharmacopoeia monograph (Ph Eur 0417).
A-10 Aircraft Oxygen Equipment Committee
Continuous Flow Oxygen RegulatorAS1197B (Current)8/23/2023
This standard covers regulators of the following types: Type I - Automatic Continuous Flow Type II - Adjustable Continuous Flow Type III - Pre-Set Continuous Flow Class A - Cylinder Mounted Class B - Line Mounted
A-10 Aircraft Oxygen Equipment Committee
Solution, Fluorescent Penetrant Water Base for LOX (Liquid Oxygen) CompatibilityAMS3158E (Current)6/27/2023
This specification covers a stable, noncorrosive, water-soluble, highly-penetrating, fluorescent solution which may, but need not, be diluted with an appropriate amount of water for use.
AMS K Non Destructive Methods and Processes Committee
Soot Formation and Ignition Characteristics of Ethanol/Gasoline Blends in a Rapid Compression Machine2023-01-03854/11/2023
With the ever-increasing demand for sustainable energy, alcohol fuels have garnered interest for use in heavy duty engines. The significant infrastructure for ethanol production and blending of ethanol with gasoline make these fuels/fuel blends desirable candidates. However, development of heavy duty engine technology that is capable of burning alcohol fuels while retaining the advantages of traditional diesel combustion requires an improved understanding of the soot formation for these fuels under conditions relevant to mixing-controlled combustion. This work uses an extinction diagnostic to study the sooting tendency of ethanol and gasoline/ethanol blends ranging from E10 to E98 during ignition in a homogeneous environment. Experiments were conducted in a rapid compression machine (RCM) for compressed conditions of 20 ± 1 bar and an approximately constant temperature (± 10K) which was unique for each fuel. For a given soot volume fraction, a linear relationship was observed between ethanol content and the equivalence ratio in which that soot volume fraction was formed. Accounting for the oxygenated nature of ethanol, E85 and E98 fuels produced similar amounts of soot at a given ϕox,, suggesting other factors outside of fuel oxygen content, such as fuel morphology, impact soot formation. Ignition delay data is reported for compressed pressures of 20 ± 1 bar and compressed temperatures ranging from 633 – 670 K for E10 and 771 – 789 K for E98. Varying pressures for E10 and E98 at conditions producing similar soot volume fractions demonstrated a linear dependence of soot formation on pressure, regardless of if the pressure considered was at top dead center or peak combustion pressure. The data gleaned from this work will be used to select soot models and chemical kinetic mechanisms for RCM simulations to ultimately model heavy duty engine technology with the studied fuels.
Gross, Joseph, Chowdhury, Musharrat, Dempsey, Adam, Allen, Casey
Sustainable Hydrogen Through Solar PowerTBMG-475452/1/2023
A new kind of solar panel, developed at the University of Michigan, has achieved 9 percent efficiency in converting water into hydrogen and oxygen — mimicking a crucial step in natural photosynthesis. Outdoors, it represents a major leap in the technology, nearly 10 times more efficient than solar water-splitting experiments of its kind.
Packaging and Transportation of Oxygen EquipmentAIR5742A (Current)1/26/2023
The scope of this document is related to the particular needs of oxygen equipment with regards to packaging and transportation. The document provides guidance for handling chemical, gaseous and liquid oxygen equipment. It summarizes national and international regulations to be taken into account for transportation on land, sea and air and provides information on classification of hazardous material. The aim of this document is to summarize information on packaging and transportation of oxygen equipment. Statements and references to regulations cited herein are for information only and should not be considered as interpretation of a law. Processes to maintain cleanliness of components and subassemblies during processing and assembly or storage of work-in-progress are outside the scope of this document. Guidance on this can be obtained from ARP1176. Rules for transportation and shipment do not cover oxygen equipment installed in an interior monument, e.g., galley unit or in a fuselage section.
A-10 Aircraft Oxygen Equipment Committee
Continuous Flow Oxygen SystemsAIR825/8 (Current)1/26/2023
This SAE Aerospace Information Report (AIR) provides general information on Continuous Flow Oxygen Systems which are available, principle functions of those systems and technical approaches to be taken into account during design and realization of systems. However, particular performance specifications and detailed information of manufacturing, testing and integration of such systems is beyond the scope of this document.
A-10 Aircraft Oxygen Equipment Committee
Closed-Cycle Protective Breathing DevicesAIR825/11A (Current)1/26/2023
Closed-cycle protective breathing apparatus, commonly referred to as rebreathers, or CCBA provide trained aircrew members or ground personnel with eye and respiratory protection from toxic atmospheres.
A-10 Aircraft Oxygen Equipment Committee
The Impact of Modification on the Stability of Catalysts for Oxygen Reduction Reaction2022-01-703810/28/2022
Vulcan XC 72R was modified in two different ways (i.g., treated by the NH3 gas or urea). The impact of modification strategies was analyzed by correlating the structure and chemical properties of carbons with the catalytic activity and stability of corresponding catalysts. Pt clusters are homogeneously distributed through the nitrogen-doped carbon support. Electronegative nitrogen atoms create positive charge on neighbor carbon atoms. The increased interaction between the carbon support and PtCl62- restrains the nucleation of platinum. N2 adsorption-desorption results indicated that abundant of micropores were created and the proportion of micropores obviously increased from 2.8 % to 11.4 %. XPS measurement distinguished different N functionalities. Pyridinic-N and pyrrolic-N were introduced on the surface of carbon support. Pt/NC catalyst exhibits the best ORR performance among all as-prepared catalysts in 0.1 M KOH solution. Moreover, the stability of Pt/NC is superior with minor negative shift of 5 and 22 mV in half-wave potential after 3k and 6k cycles. The enhanced ORR activity and stability of NC could be ascribed to the uniform Pt distribution, which promotes oxygen adsorption and hinders the migration and agglomeration of Pt clusters.
Wang, Qian, Liu, Mingtao, Zhou, Lu, Li, Yunqi
Oximeter Headband Initial Characterization Test on Form, Fit, and Function22AERP10_1210/1/2022
Developing a real-time, non-intrusive blood oxygenation sensor system capable of monitoring physical parameters such as altitude acclimation and shock in the event of trauma or hemorrhage, as well as providing early detection of viremia. Massachusetts Institute of Technology Lincoln Laboratory, Lexington, Massachusetts The oximeter headband is a new physiological status monitoring system developed by Massachusetts Institute of Technology Lincoln Laboratory (MIT LL) in Lexington, Massachusetts and the Institute for Advanced Functional Fabrics of America (AFFOA) in Cambridge, Massachusetts. It was tested for form, fit, and function during an internal test held at MIT LL. The oximeter headband system consists of a custom-made, textile-based headband. It is a noninvasive, non-subcutaneous, and non-radiation-harming device that only maintains surface contact with the skin. It has been specifically designed to meet the needs of the military. The test utilized in this research assesses the first field-portable proto-type of the oximeter headband device. Data was collected from eight test participants in two test scenarios, a functional evaluation, and a form and fit assessment.
Steel Bars and Forgings 3.5Cr - 7.5Ni - 16.3Co - 1.75Mo - 0.2W - (0.09 - 0.13C) Double Vacuum Melted, Normalized, AnnealedAMS6509B (Current)9/30/2022
This specification covers a premium aircraft-quality alloy steel in the form of bars and forgings 199 square inches (1284 cm2) and under in cross section, and forging stock of any size.
AMS E Carbon and Low Alloy Steels Committee
FAR - Regulatory Requirements Covering the Use of Breathing Oxygen in AircraftAIR1389C (Current)6/27/2022
This report presents, paraphrased in tabular format, an overview of the Federal Aviation Regulations (FAR) for aircraft oxygen systems. It is intended as a ready reference for those considering the use of oxygen in aircraft and those wishing to familiarize themselves with the systems requirements for existing aircraft. This document is not intended to replace the oxygen related FAR but rather to index them in some order. For detailed information, the user is referred to the current issue of the relevant FAR paragraph referenced in this report.
A-10 Aircraft Oxygen Equipment Committee
Products of Tomorrow: June 2022TBMG-459716/1/2022
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
Relative Adhesive Wear Performance of Rolling Element Bearing Material PairsF-0078-2022-00965/10/2022
The relative adhesive wear performance of rolling element bearing material pairs was evaluated using a constant entrainment stepped slide-to-roll (SRR) test protocol. Raceway materials included M50, M50NiL, 440C, and powder metallurgy M62 (M62 PM). Rolling element materials included M50, 440C, and Si3N4. The material interfaces of both all-steel and hybrid configurations were ranked based on the survived SRR. The Si3N4 and steel hybrid pairing increased the adhesive wear resistance, reduced the tractive effort of the contact, and enabled operation with reduced component temperatures throughout each test. Post-test wear track morphology and chemistry were investigated using light microscopy, scanning electron microscopy, and energy dispersive spectroscopy. Steel alloying elements and elevated levels of oxygen were identified within the Si3N4 wear track from each hybrid material pair.
Sadinski, Robert, Hager, Carl, Prock, Dave
The Portable Helicopter Oxygen Delivery System (PHODS) in the Altitude Chamber: Cerebral and Peripheral Blood Oxygen and Perceptual VigilanceF-0078-2022-00815/10/2022
The Portable Helicopter Oxygen Delivery System (PHODS) provides supplemental oxygen (O2) to Army aircrew at altitudes up to 18,000 feet (ft) above mean sea level (MSL). Previous PHODS tests and evaluations (T&E) used conventional pulse oximetry to monitor peripheral blood O2 saturation (SpO2). The present T&E incorporates near infrared spectroscopic (NIRS) measures of regional cerebral blood O2 saturation (rSO2). Army aircrew (N = 22) assessed PHODS functionality and effectiveness in an altitude chamber during three challenges: 10 minutes of a visual reaction time test, 5 minutes of text reading, and 2 minutes of a physical workload challenge (self-paced squats). Throughout the T&E, SpO2 and rSO2 were measured continuously at ground level and at pressure altitudes of 14,000 and 17,800 ft MSL. Results indicate that the PHODS maintained constant SpO2 throughout all testing but not rSO2 in the presence of workload. The possible operational significance of this finding is discussed.
Temme, Leonard, Bowers, Bobby, Hayes, Amanda, St Onge, Paul, McAtee, Aaron
Miniaturized, Wireless Oxygen Sensor for Sick InfantsTBMG-455354/1/2022
A sensor the size of a Band-Aid can measure a baby's blood oxygen levels, a vital indication of the lungs’ effectiveness and whether the baby's tissue is receiving adequate oxygen supply. Unlike current systems used in hospitals, this miniaturized wearable device is flexible and stretchable, wireless, inexpensive, and mobile — possibly allowing the child to leave the hospital and be monitored remotely.
OSC Modelling of 3-Way Automotive Catalysts to Understand the Effect of Latent OSC on Dynamic OSC Performance2022-01-05743/29/2022
A three-way automotive catalyst's ability to store oxygen is still a crucial performance metric for modern day catalyst applications. With more stringent emissions legalisation, the oxygen storage capacity (OSC) within a catalyst can assist with converting different harmful exhaust gases such as CO, THC and NOx under transient operating conditions. Additionally, OSC is currently the only onboard catalyst performance metric recorded during a vehicle's useful life. Catalyst performance is correlated to this OSC measurement. OSC in three-way automotive catalysts can be split into two main OSC types. "Latent" OSC deep within the washcoat and "dynamic" OSC on the surface of the catalyst washcoat. Dynamic OSC is more commonly applied in the evaluation of useful OSC of the catalyst during practical operation.
Mc Grane, Liam, Douglas, Roy, Elliott, Matthew, Irwin, Kurtis, Woods, Andrew, Pedlow, Andrew
Nickel Alloy, Corrosion- and Heat-Resistant, Powder for Additive Manufacturing 52.5Ni - 19Cr - 3.0Mo - 5.1Cb (Nb) - 0.90Ti - 0.50Al - 18FeAMS7006 (Current)3/21/2022
The intended upper bound of this specification is that the particle size distribution (PSD) of powders supplied shall be <60 mesh (250 μm) and that no powder (0.0 wt%) greater than 40 mesh (425 μm) is allowed.
AMS AM Additive Manufacturing Metals
Steel, Bars and Forgings, and Forging Stock 3.1Cr - 11.5Ni - 13.5Co - 1.2Mo (0.21 - 0.25C) Vacuum Melted, Normalized and Overaged Precipitation HardenableAMS6532J (Historical)1/27/2022
This specification covers a premium aircraft-quality alloy steel in the form of bars, forgings 100 square inches (645 cm2) and under in cross-sectional area and forging stock of any size.
AMS E Carbon and Low Alloy Steels Committee
Steel, Bars and Forgings and Forging Stock 1Cr - 10Ni - 7Co - 2Mo - 1.3W - 0.1V - (0.28 - 0.32C) Vacuum Induction Melted, Vacuum Arc Remelted, Normalized and Annealed Precipitation HardenableAMS6516C (Current)11/16/2021
This specification covers a premium aircraft-quality alloy steel in the form of bars and forgings 189 in2 (1219 cm2) and under in cross-sectional area and forging stock of any size.
AMS E Carbon and Low Alloy Steels Committee
Chemical Analysis of Deposits Separated from Blocked Fuel Filters04-15-01-000210/25/2021
Biodiesel was found to be the best candidate to replace diesel fuel mainly due to being renewable, biodegradable, and non-toxic and reduce greenhouse gases, which cause global warming. Nowadays, biodiesel is blended with diesel fuel in different concentrations depending on the country of usage and is used in diesel engines. Concerns about biodiesel were raised after premature fouling of fuel filters were reported before meeting their mileage requirement. Three filters from Brazil were analyzed using different techniques (Energy Dispersive X-Ray [EDX], Fourier Transform Infrared Spectroscopy [FTIR], Thermogravimetric Analysis [TGA], Time of Flight-Secondary Ion Mass Spectrometry [ToF-SIMS], and Gas Chromatography/Mass Spectrometry [GC/MS]) to understand the chemical composition of the filter deposits and highlight the main compounds responsible for the blockage. EDX showed that the deposits are mainly composed of carbon (C) and oxygen (O) with traces of sodium (Na), calcium (Ca), iron (Fe), phosphorus (P), and other elements. FTIR showed that the dominant bands in the filter deposits spectra are attributed to C-O bonds with a broad OH peak always present. TGA showed that the deposits vaporize at three different regions with peak temperatures around 250°C, 350°C, and 480°C, which correspond to the vaporization of glycerol, sterol glucosides (SGs), and metal carboxylates, respectively. Combining the data from the previous techniques, it was concluded that the filter deposits are mainly organic in nature with glycerol and SGs as the main compounds forming the bulk of the filter deposits with metal carboxylates present in lower amounts. This conclusion was further confirmed by ToF-SIMS and GC/MS where all three compounds were detected. In addition, free sterols and monoglycerides (MGs) were also detected in the deposits with traces of diglycerides and triglycerides also present.
ELTahry, Omar, Salehi, Farnaz Motamen, Morina, Ardian, Ferrari, Lana, Farooq, Umer, Forsberg, Carina, Neville, Anne
Insulating Component, Molded, Electrical, Heat Shrinkable, Connector and Cable Accessory, Sealing Strain Relief, General Specification ForAS5258A (Current)10/13/2021
This specification covers connector and cable accessory heat shrinkable, electrical insulating, molded components fabricated from various polymer based compositions. These components are intended for use as connector and cable accessory components to provide strain relief, electrical insulation, and environmental sealing.
AE-8C1 Connectors Committee
Experimental Investigation on the Effect of Natural Based Additives on Single-Cylinder Di Diesel Engine2021-28-01309/15/2021
In this experimental study, an attempt is made to enhance the performance characteristics of diesel fuel with two different natural additives (NA). Borassus Flabelifer (NB1) and Oryza Sativa straws (NB2) were chosen as natural additives. The selected natural additives were milled for 150 hours using a planetary ball mill and their particle sizes ranging from 120 to 125 nm. The milled natural additives were doped into neat diesel using a magnetic stirrer followed by ultrasonication and their stability was ascertained. The presence of high carbon and oxygen content was noted on EDS results of milled powder. The properties of fuel were analyzed as per ASTM standards and it was observed that there was a marginal decrease in calorific value, flash point, and fire point of the fuel. Performance analysis of the fuel was carried out in a diesel engine at different load conditions and it was observed that brake thermal efficiency reduced by 1.73 % and 1.24 % for NB1 and NB2 doped diesel respectively. CO and HC emissions were reduced by 15.42% and 17.09% for NB1-based fuel and by 8% and 12.67 % for NB2-based fuel, respectively. A reduction in CO and HC emissions was observed due to the availability of excess oxygen present in the natural-based fuel. High NOx was observed as 11.49 % and 8.72 % for NB1 and NB2 based fuel respectively. Hence, it is concluded that natural-based additives shows better reduction in emissions in IC engines.
Velusamy, Raja, Annamalai, Suresh Babu, Swaminathan, Mangudi Rangawamy, Periyana Pillai, Hariharan, Ganapathy, Sakthinathan, Radhakrishnan PhD, Vignesh, Kumar, Premkumar
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